• 전기학회논문지
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• 제68권1호
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• pp.189-198
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• 2019

In recent years, visual-inertial odometry(VIO) algorithms have been extensively studied for the indoor/urban environments because it is more robust to dynamic scenes and environment changes. In this paper, we propose loosely coupled(LC) VIO algorithm that utilizes the velocity vectors from both visual odometry(VO) and inertial measurement unit(IMU) as a filter measurement of Extended Kalman filter. Our approach improves the estimation performance of a filter without adding extra sensors while maintaining simple integration framework, which treats VO as a black box. For the VO algorithm, we employed a fundamental part of the ORB-SLAM, which uses ORB features. We performed an outdoor experiment using an RGB-D camera to evaluate the accuracy of the presented algorithm. Also, we evaluated our algorithm with the public dataset to compare with other visual navigation systems.

• 로봇학회논문지
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• 제14권2호
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• pp.114-121
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• 2019

This paper presents a new benchmark system for visual odometry (VO) and monocular depth estimation (MDE). As deep learning has become a key technology in computer vision, many researchers are trying to apply deep learning to VO and MDE. Just a couple of years ago, they were independently studied in a supervised way, but now they are coupled and trained together in an unsupervised way. However, before designing fancy models and losses, we have to customize datasets to use them for training and testing. After training, the model has to be compared with the existing models, which is also a huge burden. The benchmark provides input dataset ready-to-use for VO and MDE research in 'tfrecords' format and output dataset that includes model checkpoints and inference results of the existing models. It also provides various tools for data formatting, training, and evaluation. In the experiments, the exsiting models were evaluated to verify their performances presented in the corresponding papers and we found that the evaluation result is inferior to the presented performances.

• 한국항공우주학회지
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• 제46권6호
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• pp.479-486
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• 2018

위성항법시스템이 없는 달 표면에서 탐사 로버의 신뢰성 있는 항법성능을 확보하기 위해 관성측정장치나 카메라와 같은 추가적인 센서를 활용한 항법 알고리즘이 필수적이다. 일례로 미국의 화성 탐사 로버에 스테레오 카메라를 이용한 비주얼 오도메트리(VO)가 성공적으로 사용된 바 있다. 본 논문에서는 달 유사환경의 스테레오 흑백 이미지를 입력받아 달 탐사 로버의 6 자유도 움직임을 추정하였다. 제안하는 알고리즘은 희소 이미지 정렬 기반의 준직접방식 VO를 통해 연속된 이미지간의 상대 움직임을 추정한다. 또한 비선형성에 취약한 직접방식 VO를 보완하고자 최적화 시 로버의 움직임에 따른 가중치를 비용 함수에 고려하였고, 그 가중치는 이전 단계에서 계산된 포즈의 선형 함수로 제안한다. 본 논문에서 제안하는 로버의 움직임에 따른 가중치를 통해 실제 달 환경의 특성을 반영하는 토론토 대학의 달 유사환경 데이터셋에서 VO 성능이 향상됨을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 가을 학술논문 발표대회
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• pp.47-48
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• 2022

The positioning technology that measures the position of a person or object is a key technology to deal with the location of the real coordinate system or converge the real and virtual worlds, such as digital twins, augmented reality, virtual reality, and autonomous driving. In estimating the location of a person or object at an indoor construction site, there are restrictions that it is impossible to receive location information from the outside, the communication infrastructure is insufficient, and it is difficult to install additional devices. Therefore, this study tested the direct sparse odometry algorithm, one of the visual Simultaneous Localization and Mapping (vSLAM) that estimate the current location and surrounding map using only image information, at an indoor construction site and analyzed its applicability as an indoor positioning technology. As a result, it was found that it is possible to properly estimate the surrounding map and the current location even in the indoor construction site, which has relatively few feature points. The results of this study can be used as reference data for researchers related to indoor positioning technology for construction sites in the future.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2018년도 춘계학술발표대회
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• pp.454-456
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• 2018

주율 주행과 로봇 시스템의 기술이 발전하면서 이와 관련된 영상 알고리즘들의 연구가 활발히 진행되고 있다. 제안 네트워크는 단일 영상을 이용하여 비주얼 오도메트리를 예측하는 시스템이다. 딥러닝 네트워크로 KITTI 데이터 세트를 이용하여 학습과 평가를 하며 네트워크의 입력으로는 연속된 두 개의 프레임이 들어가고 출력으로는 두 프레임간 카메라의 회전과 이동 정보가 된다. 이를 통하여 대표적으로 자동차의 주행 경로를 알 수 있으며 여러 로봇 시스템 등에서 활용할 수 있다.

• 로봇학회논문지
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• 제13권1호
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• pp.26-30
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• 2018

Planetary global localization is necessary for long-range rover missions in which communication with command center operator is throttled due to the long distance. There has been number of researches that address this problem by exploiting and matching rover surroundings with global digital elevation maps (DEM). Using conventional methods for matching, however, is challenging due to artifacts in both DEM rendered images, and/or rover 2D images caused by DEM low resolution, rover image illumination variations and small terrain features. In this work, we use train CNN discriminator to match rover 2D image with DEM rendered images using conditional Generative Adversarial Network architecture (cGAN). We then use this discriminator to search an uncertainty bound given by visual odometry (VO) error bound to estimate rover optimal location and orientation. We demonstrate our network capability to learn to translate rover image into DEM simulated image and match them using Devon Island dataset. The experimental results show that our proposed approach achieves ~74% mean average precision.